Policy templates: Replace http with https in usage examples.
Policy templates: Replace http with https in usage examples.

Using https is current best practice.  Our documentation should
reflect this instead of using/advertising an outdated protocol.

BUG=None

Review URL: https://codereview.chromium.org/1304333002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#344980}

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